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V8 runs a generational, incremental, mostly-concurrent mark-and-sweep collector. GC is triggered by heap-size thresholds — minor GC (young generation, Scavenge) fires often and is fast; major GC (Mark-Compact, full heap) fires on memory pressure or idle. You can't manually trigger it from JS, only influence it by dropping references and avoiding accidental retainers (closures, listeners, detached DOM, globals).
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